JP5302322B2 - Display with integrated photovoltaic - Google Patents

Abstract

A display with a photovoltaic (PV) cells integrated as the front side and/or back side of the display is disclosed. Ambient light may reach a PV cell situated behind a display through fully or partially transmissive features within the display. Display-generated light may also reach a PV cell behind a display. A transmissive PV material situated in front of a display may collect both ambient light as well as display-generated light.

Description

  The present invention relates generally to display devices for actively displaying images.

  Active displays can be made entirely or partially with reflective, transmissive, or emissive pixels. Thus, a display can be a pixel that operates by fully or partially reflecting incident ambient light, a pixel that is luminescent, or a transparency in which light is generated from within the display and projected onto a transmissive pixel. Images may be generated using pixels. Reflective display technologies may include liquid crystals, MEMS (such as interferometric modulators), electrophoresis (such as e-ink or e-paper), and other display technologies that use reflected ambient light to generate images. However, it is not limited to these. An emissive display is a liquid crystal display (LCD) or thin film transistor liquid crystal display (TFT LCD), or a display in which active pixels themselves generate or emit light, such as vacuum fluorescent lamps, light emitting diode LEDs, organic light emitting diodes (OLED), or surfaces Includes displays having a backlight for illuminating active transmissive pixels, such as electric field displays.

  The display can include MEMS devices such as interferometric modulators. As used herein, the term interferometric modulator or interferometric light modulator refers to a device that selectively absorbs and / or reflects light using the principles of optical interference. In some arrangements, the interferometric modulator may comprise a pair of conductive plates, one or both of which may be wholly or partially transparent and / or reflective to provide an appropriate electrical signal. When applied, it can perform relative operations. For example, one plate may comprise a stationary layer deposited on a substrate and the other plate may comprise a metal film separated from the stationary layer by an air gap. As described in more detail herein, the optical interference of light incident on the interferometric modulator can be varied depending on the position of one plate relative to the other plate. Such devices have a wide range of applications and take advantage of the characteristics of these types of devices and / or so that their features can be used to improve existing products and create new products that have not yet been developed. It would be beneficial in the art if it could be changed.

  In one embodiment, the display device displays an image on the front side and has a back side opposite the front side. The display device includes a display and a photovoltaic cell. The display includes an array region, the array region including active pixel areas and inactive areas. The photovoltaic cell includes a photovoltaic material. A photovoltaic material is formed on one of the front and back surfaces of the array region. The photovoltaic material is patterned.

  In another embodiment, a method for manufacturing a display device is provided. The display device is configured to display an image on the front side and has a back side opposite the front side. The method includes providing a display comprising an array region. The array area comprises active pixel areas and inactive areas. The method also includes disposing a patterned photovoltaic material on one of the front and back surfaces of the array region.

  In yet another embodiment, a method for collecting light for conversion to electricity is provided. The method includes receiving light into the patterned photovoltaic material at one of the front and back surfaces of the array area of the display. The method also includes converting light to electricity.

  In an alternative embodiment, the display device displays the image on the front side and has a back side opposite the front side. The display device includes means for displaying a variable pixelated image and means for converting light to electricity. The conversion means is patterned and arranged on one of the front and back surfaces of the display means.

  Exemplary embodiments disclosed herein are shown in the accompanying schematic drawings, which are for illustrative purposes only. The following figures are not necessarily drawn to scale.

FIG. 3 is an isometric view showing a portion of one embodiment of an interferometric modulator display, wherein the movable reflective layer of the first interferometric modulator is in a relaxed position and the movable reflective layer of the second interferometric modulator is in an operational position. It is in. FIG. 3 is a system block diagram illustrating one embodiment of an electronic device incorporating a 3 × 3 interferometric modulator display. 2 is a diagram of movable mirror position versus applied voltage for one exemplary embodiment of the interferometric modulator of FIG. FIG. 6 is a set of row and column voltages that can be used to drive an interferometric modulator display. FIG. 3 is an exemplary timing diagram for row and column signals that may be used to write a frame of display data to the 3 × 3 interferometric modulator display of FIG. 2. FIG. 3 is an exemplary timing diagram for row and column signals that may be used to write a frame of display data to the 3 × 3 interferometric modulator display of FIG. 2. FIG. 2 is a system block diagram illustrating an embodiment of a visual display device comprising a plurality of interferometric modulators. FIG. 2 is a system block diagram illustrating an embodiment of a visual display device comprising a plurality of interferometric modulators. FIG. 2 is a cross-sectional view of the device of FIG. FIG. 6 is a cross-sectional view of an alternative embodiment of an interferometric modulator. FIG. 6 is a cross-sectional view of another alternative embodiment of an interferometric modulator. FIG. 6 is a cross-sectional view of yet another alternative embodiment of an interferometric modulator. FIG. 6 is a cross-sectional view of a further alternative embodiment of an interferometric modulator. FIG. 6 is a bottom view of an array of interferometric modulators. It is the schematic of a photovoltaic cell provided with a pn junction. FIG. 2 is a block diagram schematically illustrating a photovoltaic cell comprising a deposited thin film photovoltaic active material. FIG. 2 is a block diagram schematically illustrating a photovoltaic cell comprising a photovoltaic stack enhanced with interferometry. FIG. 2 shows a display having an array of active pixels and inactive areas between pixels. FIG. 6 is a schematic cross-sectional view for purposes of illustrating a possible light source of external light in an inactive area of a display having an array of active pixels and an inactive area. FIG. 6 is a schematic cross-sectional view of a display having an array of active pixels and inactive areas, with a patterned PV black mask formed in front of the active pixels. FIG. 6 is a schematic cross-sectional view of a display having an array of active pixels and inactive areas with a patterned PV black mask formed behind the active pixels. FIG. 3 is a schematic isometric view of an interferometric array with a patterned PV black mask formed behind the array. 1 is a schematic cross-sectional view of one embodiment of an interferometric modulator having an integrated front PV black mask. FIG. FIG. 6 is a schematic cross-sectional view of another embodiment of an interferometric modulator having an integrated backside PV black mask. FIG. 2 is a schematic cross-sectional view showing the first step in an embodiment of a method for making a PV black mask. 2 is a schematic cross-sectional view illustrating an embodiment for patterning a photovoltaic material to form a PV black mask and a method of interconnecting the insulated features of a patterned PV black mask. FIG. 2 is a schematic cross-sectional view illustrating an embodiment for patterning a photovoltaic material to form a PV black mask and a method of interconnecting the insulated features of a patterned PV black mask. FIG.

  Although specific embodiments and examples are discussed herein, this novel content extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses of the invention and its obviousness. It will be understood that this extends to various modifications and equivalents. It is intended that the scope of the invention disclosed herein should not be limited by any particular disclosed embodiment. Thus, for example, in any methods or processes disclosed herein, the actions or operations that make up the methods / processes may be performed in any suitable order and are limited to any particular disclosed order. There is no need. Various aspects and advantages of the embodiments are described as appropriate. It should be understood that not necessarily all such aspects or advantages may be realized in any particular embodiment. Thus, for example, various advantages may be achieved in a manner that realizes or optimizes one advantage or group of advantages taught herein without necessarily realizing the other aspects or advantages taught or suggested herein. It should be understood that embodiments may be implemented. The following detailed description is directed to certain specific embodiments of the invention. However, the present invention can be implemented in a number of different ways. The embodiments described herein may be implemented with a wide range of display devices.

  Reference is made herein to the drawings, wherein like parts are designated with like numerals throughout. Embodiments of the present invention may be implemented in any device configured to display an image, whether it is a moving image (eg, a video), a still image (eg, a still image), text or an image. . More particularly, embodiments of the present invention include mobile phones, wireless devices, personal digital assistants (PDAs), portable computers or portable computers, GPS receivers / navigators, cameras, MP3 players, camcorders, game consoles. Watch, table clock, calculator, television monitor, flat panel display, computer monitor, automatic display (eg odometer display, etc.), cockpit control and / or display, camera view display (eg car rear view camera display) In various electronic devices such as, but not limited to, electronic photographs, bulletin boards or signs, projectors, buildings, packaging, and art structures (eg, image display on jewelry) In connection with the device, it is contemplated that may be implemented.

  Photovoltaic (PV) material is integrated with active displays such as emissive, transmissive, and reflective or partially reflective (transflective) displays. PV materials are inactive in displays such as gaps, spaces, holes, spacers, pillars, posts, rails, or other support structures formed from transparent, translucent materials such as air, silicon dioxide or other materials Patterned to collect area light. The PV material may be formed in front of or behind the display. The PV material may be formed in a pattern corresponding to at least some of the inactive areas of the display.

  First, FIGS. 1-7F illustrate some basic principles of an interferometric modulator (IMOD) display. Figures 8-9 illustrate some basic principles of PV cells and devices. FIGS. 10-17B illustrate an embodiment in which the display is integrated with a patterned photovoltaic (PV) material that serves to mask inactive areas of the IMOD or other types of displays.

  One interferometric modulator display embodiment comprising an interferometric MEMS display element is shown in FIG. In these devices, the pixels are in either a bright state or a dark state. In the bright state (“relaxed state” or “open state”), the display element reflects a large portion of incident visible light to the user. When the display element is in the dark state ("actuated" or "closed"), it does not reflect most of the incident visible light to the user. Depending on the embodiment, the “on state” light reflectance characteristic and the “off state” light reflectance characteristic may be reversed. MEMS pixels can be configured to reflect primarily with a selected color, allowing color display in addition to black and white display.

  FIG. 1 is an isometric view showing two adjacent pixels in a series of pixels of a visual display, each pixel comprising a MEMS interferometric modulator. In some embodiments, an interferometric modulator display comprises a row / column array of these interferometric modulators. Each interferometric modulator includes a pair of reflective layers disposed at a controllable variable distance from each other to form a resonant optical gap having at least one variable dimension. In one embodiment, one of the reflective layers may be moved between two positions. In a first position, referred to herein as a relaxed position, the movable reflective layer is disposed at a relatively large distance from the fixed partially reflective layer. In a second position, referred to herein as the actuated position, the movable reflective layer is disposed closer and adjacent to the partially reflective layer. Incident light that reflects from the two layers interferes constructively or destructively depending on the position of the movable reflective layer, resulting in an overall reflective or non-reflective state for each pixel.

  The depicted portion of the pixel array of FIG. 1 includes two adjacent interferometric modulators 12a and 12b. In the left interferometric modulator 12a, the movable reflective layer 14a is shown at a relaxed position at a predetermined distance from the optical laminate 16a including the partially reflective layer. In the right interferometric modulator 12b, the movable reflective layer 14b is shown in an operating position adjacent to the optical stack 16b.

  Optical stacks 16a and 16b (collectively referred to as optical stacks 16), as referred to herein, are electrode layers such as indium tin oxide (ITO), partially reflective layers such as chromium, And several fusion layers that can include transparent dielectrics. Thus, the optical stack 16 is electrically conductive, partially transmissive, and partially reflective, for example fabricated by depositing one or more of the above layers on the transparent substrate 20. Can be done. The partially reflective layer can be formed from a variety of partially reflective materials such as various metals, semiconductors, and dielectrics. The partially reflective layer can be formed from one or more layers of material, each of which can be formed from a single material or combination of materials.

  In some embodiments, the layers of the optical stack 16 may be patterned into parallel strips to form row electrodes in the display device, as further described below. One or more deposited metal layers (16a, 16b on the row electrodes) of a series of parallel strips deposited on top of the struts 18 and the intervening sacrificial material deposited between the struts 18 Movable reflective layers 14a, 14b (also known as “mirrors” or “reflectors”) may be formed. When the sacrificial material is etched away, the movable reflective layers 14a, 14b are separated from the optical stack 16a, 16b by a defined gap 19. A highly conductive and reflective material such as aluminum may be used for the reflective layer 14, and these strips may form the column electrodes of the display device. Note that FIG. 1 may not be scaled. In some embodiments, the spacing between the struts 18 may be on the order of 10-100 μm, while the gap 19 may be on the order of less than 1000 angstroms. The partially reflective layer may also be referred to as a light absorber. Thus, in some embodiments, an active interferometric modulator can be said to comprise an absorber and a reflector separated by a variable optical cavity or gap.

  As shown by the pixel 12a in FIG. 1, when there is no applied voltage, a gap 19 remains between the movable reflective layer 14a and the optical stack 16a, and the movable reflective layer 14a is mechanically relaxed. However, when a potential (voltage) difference is applied to the selected row and column, the capacitor formed at the intersection of the row electrode and column electrode of the corresponding pixel is charged and electrostatic force attracts the electrodes to each other. When the voltage is sufficiently high, the movable reflective layer 14 is deformed and pressed against the optical laminate 16. As shown by the actuated pixel 12b on the right side of FIG. 1, a dielectric layer (not shown in this figure) in the optical stack 16 prevents a short circuit between the layers 14 and 16. The separation distance can be controlled. The behavior is the same regardless of the polarity of the applied potential difference.

  2-5 illustrate one exemplary process and system that uses an array of interferometric modulators in a display application.

  FIG. 2 is a system block diagram illustrating one embodiment of an electronic device that may incorporate an interferometric modulator. The electronic device can be ARM®, Pentium®, 8051, MIPS®, Power PC®, or ALPHA®, or a digital signal processor, microcontroller, or programmable gate array. Including a processor 21, which may be any general purpose single chip microprocessor or general purpose multichip microprocessor, such as any dedicated microprocessor. As is common in the art, the processor 21 may be configured to execute one or more software modules. In addition to executing the operating system, the processor may be configured to execute one or more software applications including a web browser, a telephone application, an email program, or any other software application.

  In one embodiment, the processor 21 is also configured to communicate with the array driver 22. In one embodiment, the array driver 22 includes a row drive circuit 24 and a column drive circuit 26 that provide signals to the display array or panel 30. The cross section of the array shown in FIG. 1 is shown by line 1-1 in FIG. Although FIG. 2 shows a 3 × 3 array of interferometric modulators for clarity, the display array 30 may include a large number of interferometric modulators, and different interferometric types in rows and columns. Note that there may be a number of modulators (eg, 300 pixels per row x 190 pixels per column).

  FIG. 3 is a diagram of movable mirror position versus applied voltage for one exemplary embodiment of the interferometric modulator of FIG. In the case of MEMS interferometric modulators, the row / column actuation protocol may take advantage of the hysteresis characteristics of those devices shown in FIG. For example, an interferometric modulator may require a potential difference of 10 volts to deform the movable layer from a relaxed state to an activated state. However, when the voltage drops from 10 volts, the movable layer maintains its state as the voltage drops below 10 volts. In the exemplary embodiment of FIG. 3, the movable layer does not relax completely until the voltage drops below 2 volts. Thus, in the embodiment shown in FIG. 3, there is a voltage range of about 3-7V and there is a window of applied voltage within which the device is either in a relaxed state or an operating state. Even if it is, it is stable. This is referred to herein as a “hysteresis window” or “stable window”. In the case of the display array having the hysteresis characteristic of FIG. 3, during the row strobe, the pixels to be actuated in the strobed row receive a voltage difference of about 10 volts and the pixels to be relaxed receive a voltage difference close to zero volts. In addition, a row / column actuation protocol can be designed. After the strobe, the pixels are subjected to a steady state or bias voltage difference of about 5 volts so that they remain in whatever state they are placed by the row strobe. After being written, each pixel experiences a potential difference within a “stable window” of 3-7 volts in this example. This feature makes the pixel design shown in FIG. 1 stable under conditions of the same applied voltage in existing operating or relaxed states. Since each pixel of the interferometric modulator is basically a capacitor formed by a fixed reflective layer and a movable reflective layer, both in the actuated state and in the relaxed state, this stable state is almost a power loss with a voltage within the hysteresis window. Can be maintained without. Basically, if the applied potential is fixed, no current flows into the pixel.

  As described further below, in a typical application, a set of data signals (each having a particular voltage level) across the set of column electrodes as per the desired set of activated pixels in the first row. A frame of an image can be created. A row pulse is then applied to the first row of electrodes that activate the pixels corresponding to this set of data signals. This set of data signals is then changed to correspond to the desired set of activated pixels in the second column. A pulse is then applied to the second row of electrodes, actuating the appropriate pixels in the second row in accordance with the data signal. The pixels in the first row are not affected by the pulse in the second row and remain in the state set during the pulse in the first row. This may be repeated for all rows in a sequential manner to generate a frame. In general, by repeating this process at some desired number of frames per second, the frames are refreshed and / or updated with new image data. A wide variety of protocols for driving the pixel array row and column electrodes may be used to generate the image frame.

FIGS. 4 and 5 illustrate one possible operating protocol for creating a display frame on the 3 × 3 array of FIG. FIG. 4 shows a possible set of column and row voltage levels that may be used for the pixel showing the hysteresis curve of FIG. In the embodiment of FIG. 4, the operation of the pixel includes setting the appropriate column to −V _bias and the appropriate row to + ΔV, which correspond to −5 volts and +5 volts, respectively. It's okay. Pixel relaxation is accomplished by setting the appropriate column to + V _bias and the appropriate row to the same + ΔV to produce a zero volt potential difference across the pixel. In those rows where the row voltage is maintained at zero volts, the pixel is stable regardless of its original state, whether the column is + V _bias or -V _bias . Also, as shown in FIG. 4, a voltage of the opposite polarity as described above can be used, for example, pixel operation sets the appropriate column to + V _bias and the appropriate row to −ΔV. Can be included. In this embodiment, pixel release is accomplished by setting the appropriate column to -V _bias and the appropriate row to the same -ΔV to produce a zero volt potential difference across the pixel.

  FIG. 5B is a timing diagram showing a series of row and column signals applied to the 3 × 3 array of FIG. 2, which will result in the display mechanism shown in FIG. 5A. Here, the actuated pixels are non-reflective. Prior to writing the frame shown in FIG. 5A, the pixels can be in any state, and in this example, all rows are initially 0 volts and all columns are +5 volts. With these applied voltages, all pixels are stable in their current operating or relaxed state.

  In the frame of FIG. 5A, pixels (1,1), (1,2), (2,2), (3,2) and (3,3) are activated. To accomplish this, during the “line time” of row 1, columns 1 and 2 are set to −5 volts, and column 3 is set to +5 volts. Since all pixels remain in the 3-7 volt stability window, the state of any pixel is not changed by this. Row 1 is then strobed with a pulse that goes from 0 volts to 5 volts and back to zero. This activates pixels (1,1) and (1,2) and relaxes pixel (1,3). Other pixels in the array are not affected. To set row 2 as desired, column 2 is set to -5 volts, and columns 1 and 3 are set to +5 volts. The same strobe applied to row 2 will then actuate pixel (2,2) and relax pixels (2,1) and (2,3). Similarly, the other pixels of the array are not affected. Row 3 is similarly set by setting columns 2 and 3 to -5 volts, and column 1 to +5 volts. With the row 3 strobe, the row 3 pixels are set as shown in FIG. 5A. After writing to the frame, the row potential is zero and the column potential can remain at +5 volts or -5 volts, at which time the display is stable with the mechanism of FIG. 5A. The same procedure can be used for arrays of dozens or hundreds of rows and columns. The timing, sequence, and level of voltages used to perform row and column operations can vary widely within the general principles outlined above, and the above embodiments are merely Illustrative, any actuation voltage method can be used with the systems and methods described herein.

  6A and 6B are system block diagrams illustrating an embodiment of display device 40. The display device 40 can be, for example, a mobile phone or a mobile phone. However, the same components of display device 40 or slight variations thereof are also illustrative of various types of display devices such as televisions and portable media players.

  The display device 40 includes a container 41, a display 30, an antenna 43, a speaker 45, an input device 48, and a microphone 46. The container 41 is generally formed from any of a variety of manufacturing processes, including injection molding and vacuum forming. Further, the container 41 may be made from any of a variety of materials, including but not limited to plastic, metal, glass, rubber, and ceramic, or combinations thereof. In one embodiment, the container 41 includes a removable portion (not shown) that can be replaced with other removable portions, including various colors or various logos, images, or symbols.

  The display 30 of the exemplary display device 40 can be any of a variety of displays, including a bi-stable display, as described herein. In other embodiments, display 30 includes a flat panel display such as plasma, EL, OLED, STN LCD, or TFT LCD as described above, or a non-flat panel display such as a CRT or other electron tube device. However, for purposes of describing the present embodiment, the display 30 includes an interferometric modulator display, as described herein.

  The components of one embodiment of exemplary display device 40 are schematically illustrated in FIG. 6B. The illustrated exemplary display device 40 includes a container 41, which can include additional components that are at least partially sealed. For example, in one embodiment, the exemplary display device 40 includes a network interface 27 that includes an antenna 43 coupled to a transceiver 47. The transceiver 47 is connected to the processor 21, and the processor 21 is connected to the adjustment hardware 52. The conditioning hardware 52 may be configured to condition the signal (eg, filter the signal). The adjustment hardware 52 is connected to the speaker 45 and the microphone 46. The processor 21 is also connected to an input device 48 and a driver controller 29. Driver controller 29 is coupled to frame buffer 28 and array driver 22, and array driver 22 is coupled to display array 30. The power supply 50 provides power to all components required by the particular exemplary display device 40 design.

  The network interface 27 includes an antenna 43 and a transceiver 47 so that the exemplary display device 40 can communicate with one or more devices over a network. In one embodiment, the network interface 27 may have a number of processing capabilities to ease the processor 21 requirements. The antenna 43 is an arbitrary antenna for transmitting and receiving signals. In one embodiment, the antenna transmits and receives RF signals according to the IEEE 802.11 standard, including IEEE 802.11 (a), (b), or (g). In another embodiment, the antenna transmits and receives RF signals according to the BLUETOOTH standard. In the case of a cellular phone, the antenna is designed to receive CDMA, GSM, AMPS, W-CDMA, or other known signals used to communicate within a wireless cellular network. The transceiver 47 preprocesses the signals received from the antenna 43 so that they are received and further manipulated by the processor 21. The transceiver 47 also processes the signals received from the processor 21 so that they can be transmitted from the exemplary display device 40 via the antenna 43.

  In an alternative embodiment, the transceiver 47 can be replaced with a receiver. In yet another alternative embodiment, the network interface 27 can be replaced with an image source, which can store or generate image data that is sent to the processor 21. For example, the image source can be a digital video disc (DVD) or hard disk drive containing image data, or a software module that generates image data.

  The processor 21 generally controls the overall operation of the exemplary display device 40. The processor 21 receives data such as compressed image data from the network interface 27 or image source and processes this data into raw image data or a format that can be easily processed into raw image data. Next, the processor 21 sends the processing data to the driver controller 29 or the storage frame buffer 28. Raw data generally refers to information that identifies the image characteristics at each position in the image. For example, such image characteristics can include color, saturation, and gray scale level.

  In one embodiment, the processor 21 includes a microcontroller, CPU, or logic unit for controlling the operation of the exemplary display device 40. The conditioning hardware 52 generally includes an amplifier and a filter for transmitting signals to the speaker 45 and receiving signals from the microphone 46. The conditioning hardware 52 may be a separate component within the exemplary display device 40 or may be incorporated within the processor 21 or other component.

  The driver controller 29 receives the raw image data generated by the processor 21 directly from the processor 21 or from the frame buffer 28 and transmits the raw image data appropriately to the array driver 22 for high-speed transmission. Reformat. Specifically, the driver controller 29 reformats the raw image data into a data stream having a raster-like format so that it has a time sequence appropriate for scanning across the display array 30. The driver controller 29 then sends the formatted information to the array driver 22. A driver controller 29, such as an LCD controller, is often associated with the system processor 21 as a stand-alone integrated circuit (IC), but such a controller may be implemented in many ways. They may be incorporated into the processor 21 as hardware, may be incorporated into the processor 21 as software, or may be fully integrated with the hardware along with the array driver 22.

  In general, the array driver 22 receives formatted information from the driver controller 29 and applies video data many times per second to hundreds (sometimes thousands) of leads coming from the xy matrix of pixels of the display. Reformat to a parallel set of waveforms.

  In one embodiment, driver controller 29, array driver 22, and display array 30 are suitable for any of the display types described herein. For example, in one embodiment, driver controller 29 is a conventional display controller or a bistable display controller (eg, an interferometric modulator controller). In another embodiment, the array driver 22 is a conventional drive circuit or a bistable display drive circuit (eg, an interferometric modulator display). In one embodiment, the driver controller 29 is integrated with the array driver 22. Such an embodiment is common in highly integrated systems such as cellular phones, watches, and other small area displays. In yet another embodiment, display array 30 is a general display array or a bi-stable display array (eg, a display that includes an array of interferometric modulators).

  Input device 48 allows a user to control the operation of exemplary display device 40. In one embodiment, the input device 48 includes a keypad, such as a QWERTY keyboard or a telephone keypad, push buttons, switches, touch screens, or a pressure sensitive or heat sensitive membrane. In one embodiment, the microphone 46 is an input device for the exemplary display device 40. When the microphone 46 is used to input data to the device, voice commands can be provided by the user to control the operation of the exemplary display device 40.

  As is well known in the art, the power supply 50 can include a variety of energy storage devices. For example, in one embodiment, the power supply 50 is a rechargeable battery, such as a nickel cadmium battery or a lithium ion battery. In another embodiment, power supply 50 is a renewable energy source, a capacitor, or a solar cell that includes plastic solar cells and solar cell paints. In another embodiment, power supply 50 is configured to receive power from a wall outlet.

  In some implementations, as described above, the functionality of the control program resides in a driver controller that can be located at several locations in the electronic display system. In some cases, the functionality of the control program resides in the array driver 22. The aforementioned optimization may be performed with any number of hardware and / or software components and in various configurations.

  The details of the structure of interferometric modulators that operate according to the principles described above can vary widely. For example, FIGS. 7A-7E illustrate five separate embodiments of the movable reflective layer 14 and its support structure. FIG. 7A is a cross section of the embodiment of FIG. 1, in which an elongated metal material 14 that serves as both a mechanical reflective layer and a movable reflective layer is deposited on a vertically extending support 18. In FIG. 7B, the movable reflective layer 14 of each interferometric modulator is square or rectangular and is attached to the support 18 in contact with the tether 32 only at the corners. In FIG. 7C, the movable reflective layer 14 is square or rectangular and is suspended from a deformable layer 34 that may include a flexible metal. The deformable layer 34 connects directly or indirectly to the substrate 20 around the periphery of the deformable layer 34. These connections are referred to herein as supports 18 and can take the form of struts, rails or walls. In the embodiment shown in FIG. 7D, the support 18 includes a post plug 42 upon which a deformable layer 34 is supported. As shown in FIGS. 7A-7C, the movable reflective layer 14 remains suspended over the optical cavity or gap, but can be deformed by filling a hole between the deformable layer 34 and the optical stack 16. The layer 34 does not form a support. Rather, the support 18 is formed from a planarizing material that is used to form the strut plug 42. The embodiment shown in FIG. 7E is based on the embodiment shown in FIG. 7D, but is not shown in any of the embodiments shown in FIGS. 7A-7C, as well as in the figure. It can also be adapted to handle not additional embodiments. In the embodiment shown in FIG. 7E, an additional layer of metal or other conductive material is used to form the bus structure 44. This allows routing of signals along the back of the interferometric modulator and eliminates the need to form a number of electrodes on the substrate 20.

  7A-E, the interferometric modulator functions as a direct view device, and the image is viewed from the front surface of the transparent substrate 20 (opposite the surface on which the interferometric modulator is disposed). It is done. In these embodiments, the reflective layer 14 optically shields the portion of the interferometric modulator on the side of the reflective layer opposite the substrate 20, including the deformable layer 34. This allows the shielded area to be configured and operated without adversely affecting image quality. For example, such shielding allows the bus structure 44 of FIG. 7E to provide the ability to separate the optical properties of the modulator from the electromechanical properties of the modulator, such as addressing and motion due to that addressing. Become. This separable modulator configuration allows structural designs and materials that are used to select and function the electromechanical and optical aspects of the modulator independently of each other. Further, the embodiment shown in FIGS. 7C-7E has the additional benefit obtained by separating the optical properties of the reflective layer 14 achieved by the deformable layer 34 from its mechanical properties. This allows the structural design and material used for the reflective layer 14 to be optimized with respect to optical properties, and the structural design and material used for the deformable layer 34 to be optimized with respect to desired mechanical properties. Become.

  FIG. 7F is a back view of an array of interferometric modulators. Four complete pixels are shown in a larger array arranged in a grid. It can be seen that the deformable or mechanical layer 34 (which can also serve as the movable reflector 14 in a simple embodiment such as FIG. 7A) is patterned to form the column electrode 71. The conductive layer (see optical stack 16 in FIG. 1) disposed under the air gap is patterned to form row electrodes 72 separated by rail support 73 in FIG. 7F, thereby deformable. Enables operation of specific parts of the layer. A gap 74 separates the strips of column electrode 71. A column or support structure 75 may be formed in a particular pixel to stiffen the mechanical layer. Furthermore, etching holes 76 are formed through the mechanical layer 34 throughout the array. When the deformable reflective layer is activated, a portion of the column electrode 71 may approach the row electrode 72 and the activated portion of the array may appear dark throughout the array. However, the array is switchable between a non-actuated position that reflects the first color and an actuated position that reflects the second color, or is dark at the actuated position if another dimension or material is utilized. It will be appreciated that various configurations may be used, such as those that do not need to be. Rail support 73 and gap 74 form an inactive area between active pixels 77. Regions such as the support structure 75 within the active pixel 77 may also be considered “inactive areas”, as will the etch hole 76 in the absence of a separate reflector 14 hanging. In fact, the area surrounding each support structure 75 and the area adjacent to and adjacent to the rail support 73 can also be considered “inactive” because the mirror layer cannot be completely collapsed in these areas. It is possible to mask these areas so that the surrounding areas surrounding the support structure do not act differently between the activated and deactivated states. As discussed further below, the emission, reflection, or transmission of light from inactive areas can degrade the impression of the image by the viewer.

  Certain embodiments disclosed herein include devices integrated with photovoltaic (PV) batteries or displays comprising MEMS, LCD, LEDs, or other display technologies. Such a display may actively display images or information and simultaneously collect ambient light and / or light generated by the display for conversion to electricity. Thus, an active (programmable) outdoor display may advantageously convert unused sunlight into electricity, or a display on a mobile device will help compensate for the use of standby power by collecting ambient light. You can do it. In addition, as described further below, light absorption by PV material integrated into the display may be used to mask unwanted or external light that may degrade the image. Thus, the manufacturing cost of integrating PV material into the display can be at least partially offset by omitting another step to form a mask in the inactive areas of the display image area.

  In some embodiments, the transmissive PV cell may overlie the image area of the display. The PV active material is contained within the active image area or array area of the display device so as to capture unused ambient light or light generated by the display and convert it to electricity. Depending on the technology of the active display, up to 30% or more of the surface area of the array area of the display may actually consist of inactive areas or areas that do not contribute to the pixelated image or displayed information. This means that within 30% or more of the ambient light incident on the active image area of the display is “wasted” and thus may be acquired by the PV material for useful conversion to electricity. This can be achieved by placing a patterned PV material behind the display so that ambient light incident on the display is illuminated or transmitted through the inactive areas of the display onto the underlying patterned PV material. It becomes possible to do.

  Alternatively, the patterned PV material may be formed in front of the inactive area, and light striking the inactive area of the display that would otherwise be wasted can then be masked by the patterned PV material. These lights can actually degrade the image of the display device. Therefore, it is advantageous to form a black mask to mask these inactive areas to prevent unwanted radiation or reflection to the viewer. In order to maintain the desired contrast, the black mask preferably includes a photovoltaic material to form a PV black mask so as to favorably convert unwanted light into useful electricity as well as absorbing. It's okay.

  FIG. 8 schematically illustrates an example of a photovoltaic (PV) battery 80. A typical photovoltaic cell can convert light energy into electrical energy or current. PV cell 80 is an example of a renewable energy source that has a small carbon footprint and a low environmental impact. When a PV battery is used, the cost of energy generation can be reduced. PV cells can have many different sizes and shapes, for example, from smaller than postage stamps to sizes over several inches. PV modules can include electrical connections, mounting hardware, power conditioning equipment, and a battery that stores solar energy for use in the absence of sunlight.

  A typical PV battery 80 includes a PV material 81 disposed between two electrodes 82 and 83. In some embodiments, the PV cell 80 comprises a substrate on which a stack of layers is formed. The PV material 81 of the PV battery 80 may include a semiconductor material such as silicon. In some embodiments, the active region may comprise a pn junction formed by contacting an n-type semiconductor material 81a and a p-type semiconductor material 81b, as shown in FIG. Such a pn junction may have characteristics similar to a diode and may therefore be referred to as a photodiode structure.

PV material 81 is generally sandwiched between two electrodes that provide a current path. The electrodes 82, 83 can be formed from aluminum, silver, or molybdenum or some other conductive material. The electrodes 82, 83 may also be formed or included from a transparent conductive material. The electrodes 82, 83 may be designed to cover most of the front surface of the pn junction so as to reduce contact resistance and improve collection efficiency. In embodiments where the electrodes 82, 83 are formed from an opaque material, the electrodes 82, 83 are configured to leave an opening above the front of the PV material to allow the PV material to be illuminated. It's okay. In some embodiments, the back electrode 82 or the front electrode 83 may comprise a transparent conductor that is a transparent conductive oxide (TCO) such as, for example, tin oxide (SnO ₂ ) or indium tin oxide (ITO). it can. TCO provides electrical contact and electrical conductivity while being transparent to incoming light. As shown, the PV cell 80 also includes an anti-reflective (AR) coating 84 disposed over the front electrode 83, although the front and back PV black masks 110, 115 (discussed further in FIGS. 12 and 13 below). In embodiments where light can be expected to pass through the back of the PV cell 80 (as in FIG. 2), an AR coating may optionally be disposed on the back electrode 82. The AR coating 84 can reduce the amount of light reflected from the front surface of the PV active material 81.

  When the PV material 81 is irradiated, photons transfer energy to electrons in the active region. If the energy transferred by the photons is larger than the band gap of the semiconductor material, the electrons can have enough energy to enter the conduction band. An internal electric field is generated with the formation of the pn junction. The internal electric field acts to move these electrons relative to the energized electrons, thereby causing a current flow in the external circuit 85. The resulting current flow can be used to power various electrical devices. For example, the resulting current flow may be stored for later use by charging a battery 86 or capacitor as shown in FIG. 8, which can provide power to the display.

  PV materials are crystalline silicon (c-silicon), amorphous silicon (a-silicon), germanium (Ge), Ge alloy, cadmium telluride (CdTe), copper indium diselenide (CIS), copper indium gallium diselenide. (CIGS), any of a variety of light-absorbing photovoltaic materials, such as light-absorbing dyes and polymers, polymers dispersed with light-absorbing nanoparticles, or cascades of multi-junction photovoltaic materials and films Things can be included. PV active material 81 may include other suitable III-V semiconductor materials including materials such as gallium arsenide (GaAs), indium nitride (InN), gallium nitride (GaN), boron arsenide (BAs). Material may be included. A semiconductor alloy such as indium gallium nitride may also be used. Other photovoltaic materials and devices are possible. Methods for forming these materials are known to those skilled in the art. As an illustrative example, an alloy such as CIGS may be formed by a vacuum-based process in which copper, gallium, and indium are co-deposited or co-sputtered and then annealed with selenide vapor to form a CIGS structure. it can. Alternative processes that are not vacuum based are also known to those skilled in the art. The deposited thin film PV active material can comprise, for example, an amorphous silicon thin film and has recently gained popularity. Amorphous silicon as a thin film can be formed by physical vapor deposition (PVD), chemical vapor deposition (CVD), electrochemical vapor deposition, or plasma enhanced chemical vapor deposition (PECVD), among other techniques. ) Can be deposited over a large area. As known to those skilled in the art, a PV active material comprising an amorphous silicon layer may include one or more junctions with n-type doped and / or p-type doped silicon, p-i-n A bond may further be provided. Other materials may also be used. The light-absorbing material (s) in which photons are absorbed and energy is transferred to electrical carriers (holes and electrons) are referred to herein as PV active layer or PV cell materials. Is intended to encompass a plurality of active sublayers. The material for the PV material can be selected depending on the desired performance and the application of the PV battery.

  FIG. 9A is a block diagram schematically showing a general thin film PV battery 90B. A general thin film PV battery 90B includes a glass substrate 91 through which light can pass. On the glass substrate 91, a first electrode layer 83, a PV material 81 (shown as including amorphous silicon) and a second electrode layer 82 are disposed. The first electrode layer 83 can include or be formed of a transparent conductive material such as ITO. As illustrated, the first electrode layer 83 and the second electrode layer 82 sandwich the thin film PV material 81 therebetween. The PV material 81 shown includes an amorphous silicon layer, although other PV thin film materials are also known. As is known in the art, amorphous silicon that functions as a PV material may include one or more diode junctions. Furthermore, the one or more amorphous silicon PV layers may comprise a pin junction in which an intrinsic silicon layer 81c is sandwiched between a p-type doped layer 81b and an n-type doped layer 81a. A pin junction can have a higher efficiency than a pn junction. In some other embodiments, the PV cell can comprise multiple junctions.

  The layers 81, 82, 83 may be deposited using a deposition method such as physical vapor deposition, chemical vapor deposition, or electrochemical vapor deposition. Thin film PV cells may include amorphous or polycrystalline materials such as thin film silicon, CIS, CdTe or CIGS. Some advantages of thin film PV cells include, among other things, a small device footprint and scalability of the manufacturing process.

  FIG. 9B illustrates one example of a PV stack or PV cell 90B enhanced with interferometry. The PV cell 90B enhanced with interferometry includes a PV active material or PV layer 81. The PV material 81 may include a thin film photovoltaic material formed on the substrate 91. The optical resonant cavity 93 and the reflector 94 disposed under the PV material 81 are configured to increase the strength of the electric field in the PV material 81 by interferometry, and the high-efficiency PV enhanced by interferometry. Battery 90B is provided. The electrode 92 covering the PV material 81 is metal in some areas that facilitate the conduction of electrons and / or holes from the PV material 81 and may be thick enough to be opaque. Otherwise, the PV material 81 may also be covered with a transparent conductive oxide (TCO) layer or an electrode 92 comprising both a TCO layer and an opaque electrode. Similarly, the optical resonant cavity 93 may comprise a TCO layer that serves as both a portion of the optical resonant cavity 93 and a conductive layer for conducting holes and / or electrons from the PV material 81. The PV material 81 may comprise a thin film photovoltaic material, such as amorphous silicon, CIGS or other thin semiconductor film photovoltaic material. The optical properties (dimensions and material properties) of the reflector 94 and the optical resonant cavity 93 are such that the reflection from the interface of the layered PV device 90B is coherent and the light energy is converted to electrical energy. A suitable wavelength distribution and phase-enhanced electric field is selected in the PV material 81 of the PV cell 90B. Such an interferometric enhanced photovoltaic device increases the absorption of light energy in the active region of the interferometric photovoltaic cell, thereby improving the efficiency of the device. In a variation on this embodiment, multiple optical resonant cavities can be used to tune different wavelengths of light separately and maximize absorption in the PV material (s). The buried optical resonant cavity and / or layer may comprise a transparent conductive or dielectric material, an air gap, or a combination thereof.

  The following embodiments describe a photovoltaic cell that incorporates or integrates a photovoltaic cell into a display device, since certain advantages are obtained by integrating the PV cell into the display. The photovoltaic cell may be arranged to capture and convert light incident on the display, light reflected from the display, or light generated by the display into electricity. Furthermore, as will be described further below, many displays are susceptible to light emitted or reflected toward the viewer in the area between pixels. This undesired light can degrade the image generated by the display by reducing the image quality and / or contrast of the display. As a result, the display can include a black mask to mask this unwanted or external light from reaching the viewer. Because this PV light can be absorbed by the PV material, the PV material may be used as a black mask for a radioactive, reflective, or transmissive display. PV black masks not only absorb unwanted light, but also advantageously convert the absorbed light to electricity, thus serving two functions and eliminating the need to form additional black masks.

  FIG. 10 shows a generalized schematic of a display device 100 that displays an image on the front or image plane of the device. As shown, display device 100 comprises an array region comprising active pixels 101. The active pixel 101 may be referred to as an active pixel area. Display device 100 also includes an inactive area. As shown, the inactive area grid lines 102, 103 are arranged between adjacent active pixels 101, ie, separating adjacent active pixels 101. In embodiments where the display device 100 is an interferometric modulator display, the inactive areas are gaps between electrodes, gaps between peripheral regions at the edge of the pixel array, rails, as discussed above with respect to FIG. 7F. There may be a gap between, a gap between support structures, or a gap between etching holes. In other embodiments, including other display technologies, the inactive areas may comprise other areas within the display that are susceptible to radiated or reflected external light.

  Also shown in FIG. 10 are rays 104 and 105 representing external light that is emitted, reflected or transmitted toward the viewer. Such light 104, 105 is often white light, but the external light towards the viewer can be any color. Such external light can degrade the image displayed on the display device 100 by whitening (either on or off) the pixel area intended to be bright, or by reducing contrast. There is. In some embodiments, the display device 100 may be connected to the external light 104, such that only light 106 from the active pixel 101 reaches the viewer and only a small amount of external light 104, 105 is directed toward the viewer. A black mask material for masking 105 may be included.

  FIG. 11 schematically shows a cross section of a typical active (programmable) display device similar to that of FIG. As shown in FIG. 11, light emitted, reflected, or transmitted from the display towards the viewer produces light 106 that is emitted, reflected, or transmitted from the active pixel 101 to form part of the image. May include. Light that is emitted, reflected, or transmitted toward the viewer may also include light 105 a-105 d that is emitted, reflected, or transmitted from the inactive area 103. The light 105a to 105d from the inactive area may cause the image displayed to the viewer to become whitish or reduce the contrast. Therefore, it is desirable to mask these areas so as to block or absorb external light 105a-105d.

  Light 105a-105d can come from many light sources. For example, the inactive area 103 may be reflective or semi-reflective. Accordingly, the light beam 105 a may be generated from the reflection of the ambient light 107 a incident on the inactive area 103. If the inactive area 103 is transparent or translucent, the light 105a can be reflected from a reflective surface or backplate 108 located behind the pixel 101. In some cases, incident ambient light 107b may pass through pixel 101 and be reflected from backplate 108, and then pass through inactive area 103 as indicated by light ray 105b. For emissive displays, the external light 105c may be emitted by a pixel 101, such as an LED display. In other displays, light may pass through the inactive area 103 from the backlight, as indicated by the light beam 105d. In all of these embodiments, the external light 105a-105d may reduce contrast or make the image whitish. A black mask made of light absorbing material can be useful to absorb this light, allowing only pixel light 106 to reach the viewer. Advantageously, this external light is not only absorbed, but is advantageously used to generate electricity for storage, to help power the display device 100, or for other applications. As such, the black mask may be made of PV material.

  FIG. 12 shows the front PV black mask 110 patterned in front of the inactive area 103 in the PV integrated display device 120. As shown, the front PV black mask 110 helps mask the inactive area 103 to absorb external light that would otherwise degrade the image displayed on the display device 120. For example, the front PV black mask 110 can absorb this light before the incident ambient light 107a is reflected. The front PV black mask 110 can also facilitate the absorption of reflected light 105b from the back plate 108 or other reflective surface disposed behind the pixel 101. As shown with respect to rays 107a and 105b, PV black mask 110 can be configured to receive light from both the front and back surfaces of the photovoltaic material. The front PV black mask 110 is emitted from the pixel 101 (for example, in the case of a radioactive pixel such as an LED display) or is transmitted through the pixel (for example when the light 105d is generated by the backlight as in an LCD display). Light 105c, 105d that deviates or scatters from the inactive area 103 may be further absorbed. Thus, as can be seen from FIG. 12, only the light 106 emitted by the active pixels 101 reaches the viewer, resulting in an improved image.

  FIG. 13 shows a PV integrated display device 130 similar to that of FIG. However, in FIG. 13, the backside PV black mask 115 is patterned behind the inactive area 103. As shown, the backside PV black mask 115 can absorb this light before the incident ambient light 107a is reflected. The backside PV black mask 115 can also facilitate the absorption of reflected light 105b from the backplate 108 or other reflective surface disposed behind the pixel 101. Thus, as shown with respect to rays 107a and 105b, backside PV black mask 115 can be configured to receive light from both the front and back sides of the photovoltaic material. The backside PV black mask 115 may further absorb light 105d that is generated by the pixel 101 but diverts or scatters into the inactive area 103. Thus, as can be seen from FIG. 13, only the light 106 emitted by the active pixels 101 reaches the viewer, resulting in an improved image. In some embodiments, the PV integrated display device may include both a front PV black mask 110 and a back PV black mask 115.

  The front PV black mask 110 shown in FIG. 12 and the back PV black mask 115 shown in FIG. 13 may comprise a photovoltaic cell that includes a photovoltaic material, as discussed above. The photovoltaic cell may comprise a photovoltaic cell enhanced by interferometry. Suitable photovoltaic materials may preferably include thin film photovoltaic materials as previously described (see FIGS. 8-9B), but semiconductor substrates or epitaxially grown semiconductor materials may also be used. It's okay. Further, as explained above, the photovoltaic material (such as PV black masks 110, 115) in the PV cell may be in contact with the electrodes. The photovoltaic material may be “sandwiched” between the electrodes. The electrodes in contact with the photovoltaic material include, for example, an opaque electrode on one side opposite the viewer, an opaque electrode on one or both sides patterned with a window to allow light to enter the PV material, and Alternatively, a film of a transparent conductive material or a transparent conductive oxide may be provided in addition to or instead of such an opaque electrode.

  As shown in FIGS. 12 and 13, the PV black masks 110 and 115 are patterned to expose the active pixels 101. For example, in some embodiments, the display is a reflective display and the PV black mask 110 is formed in front of the pixels (on the image plane). In such embodiments, the PV black mask 110 is patterned to expose the pixels 101 to incident ambient light or front light (which is selectively reflected to the viewer to generate an image). . In other embodiments, the display is transmissive and the PV black mask 115 is formed behind the pixels. In such embodiments, the PV black mask 115 is patterned to expose the pixel 101 to light from the back of the pixel (eg, backlight). In order to properly improve the image by blocking or absorbing external light, the PV black masks 110, 115 are preferably configured to reflect or transmit less than 10% of the light incident on the PV black masks 110, 115. Is done. More preferably, the PV black masks 110, 115 are configured to reflect or transmit less than 5% of visible light incident on the PV black masks 110, 115. The reflection or transmission of PV cells with PV black masks 110, 115 can depend on factors such as the thickness of the photovoltaic material in the PV cell as well as the material used. The PV black mask may also include an anti-reflective coating to further reduce reflection.

  12 and 13, the PV black masks 110, 115 are patterned to mask the inactive areas 103 of the array or image area. Thus, the PV black mask is patterned to correspond to the pattern of the inactive area 103 so as to mask unwanted optical effects (eg, reflections) of the inactive area from the viewer.

  FIG. 14 shows a perspective view of an embodiment of an array 140 of 2 × 2 PV integrated interferometric modulators. As discussed above with respect to FIG. 7F, the interferometric modulator array 140 may include an inactive area, such as a gap 74 between the row of mechanical layers 34 and the rail support 73. The inactive area may also include an etching hole 76 or a post 75 formed in the active pixel 101. In the embodiment of FIG. 14, a patterned backside PV black mask 115 is formed behind the array 140. The inactive area or image region in the array 140 may comprise a transparent inactive structure that can allow the ambient light 107b to reach the patterned backside PV black mask 115. As shown, the patterned backside PV black mask 115 is patterned to correspond to a pattern of inactive structures through which light can pass. For example, the PV black mask 115 is formed as a strip under the gap 74 and the rail 73 to form a cross pattern under or behind the array 140. For a large array, the pattern has a grid shape corresponding to the space between the active pixel regions 101. As shown, the backside PV black mask 115 may be formed on the back plate 145. Further, the backside PV black mask 115 can include “islands”, ie, unconnected portions of PV material (PV black mask islands 146).

  Advantageously, the intersecting pattern formed behind the array 140 allows the front and back electrodes of the back PV black mask 115 to be electrically connected by an external circuit to allow the display 140 to be electrically connected. It may spread to the surroundings. For embodiments of PV black masks 110, 115 that include islands such as PV black mask islands 146, the electrical connection using external circuitry may cause a blanket TCO layer in electrical contact with PV material 81 of PV black mask islands 146. (See FIG. 17A, FIG. 17B and accompanying description). In other embodiments, electrical connections using external circuitry may be made using vias, patterned metal traces, or patterned TCO films. In embodiments having patterned metal traces, the metal traces will be kept small so as not to reduce the amount of light incident on the PV material 81 in the PV black mask island 146, or the traces of the backplate 145 You can route to the back side via vias.

Examples of light passing around or between pixels 101, light passing through gaps 74, or light passing through support structure 18 or 73 (such as light ray 107a) are image areas or inactive areas within the pixel array. The use of light passing through is shown. The material can be selected to maximize the transmission through such inactive areas. Exemplary transparent materials include silicon dioxide (SiO ₂ ), titanium dioxide (TiO ₂ ), magnesium fluoride (MgF ₂ ), chromium (III) oxide film (Cr ₃ O ₂ ), silicon nitride (Si ₃ N ₄ ), and the like. The dielectric may be included. However, any transparent or partially transparent material may be used for the structures in the inactive area.

  As shown in FIG. 14, the PV active material 81 may be sandwiched between two layers of conductive material 143, 144 that can function as electrodes. The front electrode 144 can include transparent conductors such as ITO or other TCO, or can be made of these transparent conductors. It will be appreciated that the PV active material 81 may be configured to be in electrical contact with only one layer of transparent conductive material, and the back electrode 143 of the back PV black mask 115 may be opaque. .

  The transparent conductive layer may include any transparent conductive material. Many transparent conductive materials are transparent conductive oxides (TCO). TCO layers are often used with photovoltaic materials, particularly thin film photovoltaic materials, to improve electrode contact to PV materials without blocking light. Functionally, the TCO may electrically form a portion of the PV battery electrodes, which typically comprise opaque metal electrodes or conductive electrodes in electrical contact with the TCO material. For display applications, the opaque electrode may be patterned to form a large window through which the PV material can capture significant light. Alternatively, the electrodes may all be in contact with the transparent conductive material outside the image display area, and only TCO is used for the electrodes in the array or image area. As known to those skilled in the art, a typical TCO is indium tin oxide (ITO). Methods of forming or depositing ITO are well known in the art and include electron beam deposition, physical vapor deposition or sputter deposition techniques. Other TCO materials and manufacturing processes may also be used. Only the transparent conductor is required for the front electrode 144 of the back PV black mask 115 shown, but for the front PV mask 110 (see FIG. 12), a transparent conductive for the electrodes on both sides of the PV material 81. It will be appreciated that it may be useful to use the body.

  15A and 15B show two embodiments of a MEMS device that are generally similar to the embodiments shown in FIGS. 7A-7E. However, the embodiment of FIGS. 15A and 15B includes a front PV black mask 110 in front of the active pixel 101 (on the image or viewer side). As indicated by the viewer position, FIGS. 15A and 15B are inverted with respect to FIGS.

  In FIG. 15A, a buffer layer 65 of transparent material is formed on the front PV black mask 110, providing a flat surface for forming an interferometric modulator. The support 18 is aligned with the front PV black mask 110 and is approximately the same size as the cross-sectional area of the front PV black mask 110. In other embodiments, the cross-sectional area of the PV black mask 110 is not necessarily equal to the area of the support 18 and sufficiently masks this inactive area to reflect incident ambient light 107a that reflects from any surface of the interferometric modulator. To absorb, it corresponds to both the cross-sectional area and pattern of the support 18 in size and pattern. The front PV black mask 110 can exceed the support by a surface area, for example, less than 10% or less than 5%.

  As shown in FIG. 15A, the front PV black mask 110 is incorporated into the buffer layer 65 on the substrate 20. Overlying the buffer layer 65 is a light modulating element or IMOD (comprising an optical stack 16, movable layer 14, and cavity 19 separating the optical stack 16 from the movable layer 14). Also, because a portion of the buffer layer 65 is on the front PV black mask 110, the front PV black mask 110 is also electrically isolated from the support 18 and does not provide an electrical path or connection to the light modulation element.

  Alternatively, as shown in FIG. 15B, the front PV black mask 110 may be formed on the opposite side of the substrate 20 from the interferometric modulator. In this embodiment, the PV black mask may be incorporated into a similar buffer layer 65 or otherwise encapsulated on the opposite side of the substrate 20. To produce the embodiment of FIG. 15B, a display may first be formed on one side of the substrate 20. A PV black mask 110 may then be formed on the opposite side of the substrate, as discussed further below. Alternatively, the PV black mask 110 may first be formed on one side, and then the display may be formed on the opposite side.

  The various embodiments disclosed herein may be manufactured in various ways. For example, a display with an array of active pixels in the image area may be integrated into the PV black mask 110, 115 by laminating one of the patterned PV black mask and the display on the other. Alternatively, for a PV black mask placed behind the display, the PV black mask may be formed and patterned on a back plate, which may be metal or transparent, depending on the application. A back plate may then be aligned and attached to the display, forming the back surface of the display device. In other embodiments where the PV black mask is placed in front of the display, the PV black mask may be formed on a transparent cover plate such as glass or plastic. The cover plate may then be attached or laminated onto the display, or the display may then be formed or deposited on one side or the opposite side of the cover plate. Although the pattern formed by the PV black masks 110, 115 need not be the same as the pattern formed by the inactive areas, the PV black mask does not emit most of the unwanted light available in the inactive areas. The patterned PV black mask preferably covers the inactive area pattern and is aligned to the inactive area pattern so that it can be masked and absorbed.

  FIGS. 16, 17A and 17B illustrate steps in one embodiment of manufacturing a PV black mask similar to the front PV black mask 110 and the back PV black mask 115 described above. As shown in FIG. 16, the process may begin with a blanket deposition of a thin film PV material layer 81 on an electrode layer 82 on a suitable substrate 161. The substrate 161 may correspond to one side of the substrate 20 of FIGS. 15A and 15B or the opposite side. In embodiments where the PV black mask 115 is formed behind the active pixels, the substrate 161 may include the display itself such that the PV black mask 115 is formed over the back side of the display. Alternatively, similar to the embodiment of FIG. 14, the substrate 161 may include a backplate that will later be attached to the display and placed behind the display. In other embodiments, the substrate 161 may comprise a sacrificial substrate. The sacrificial substrate is then laminated to the front or back surface of the display device and removed, leaving behind a patterned PV black mask. Preferably, the stacking is done to align the pattern of PV black masks 110, 115 with the pattern of inactive areas in the pixel array.

  As will be appreciated by those skilled in the art, a black mask pattern that is continuous across the array, such as a grid pattern between pixels, is a circuit for storing charge in a battery, or the display itself or an associated electronic component (such as a mobile phone). Can be easily routed to a circuit for supplying power directly to an electrical device. Insulated PV materials, such as islands for masking the isolated pillars, may require special routing. Figures 17A and 17B illustrate one method of routing the current generated by the PV material. Alternatively, those skilled in the art will appreciate that for such islands, traces can be routed via vias to the back side of the backplate 145.

  FIG. 17A shows the device after patterning the blanket PV material layer 81 of FIG. 16 and further depositing a derivative buffer layer 171 and a second electrode 83. The dielectric buffer layer 171 can help the electrical insulation of the two electrodes 82, 83 in the region between the isolated islands of the PV material 81. The electrodes 82, 83 may comprise a transparent conductive layer, an opaque metal electrode, or both. If the electrodes 82, 83 comprise reflective or opaque metal electrodes, care should be taken to pattern the metal portions of the electrodes 82, 83 to minimize reflection and maximize the window to the PV material 81. Is preferred.

  FIG. 17B shows the device after patterning of the blanket PV material layer 81 of FIG. 16, similar to FIG. 17A above. However, in the embodiment of FIG. 17B, the electrodes 82, 83 prevent electrical contact by the thinned portion of the PV material 81, regardless of the buffer (as in FIG. 17B). Thus, although FIG. 17A patterns the PV material 81 to remove all of the PV material 81 from some areas (eg, active pixel areas), the embodiment of FIG. While the PV material 81 is patterned to be significantly thinner, in areas that are intended to serve as areas of the PV black mask 110, 115, the relatively thick PV material 81 remains.

  In general, the PV black masks 110, 115 may comprise a thin film photovoltaic material as described above. Some advantages of thin film PV cells include a small device footprint and scalability of the manufacturing process. In some embodiments, such as the embodiment of FIG. 17B, the thin film PV cell may be designed to be partially permeable. In such embodiments, the transmittance of PV material 81 within active pixel area 173 is sufficiently high so that the displayed image remains excellent outside the inactive area where PV black masks 110, 115 are desired.

  In addition, a portion of the interferometric modulator pixel may be configured or designed to be partially transmissive, so that the active pixel will pass significant ambient light to reach the PV cell 115 and its PV active material 81. It may be designed to be able to Generally, the reflector 14 includes, for example, aluminum (Al), molybdenum (Mo), zirconium (Zr), tungsten (W), iron (Fe), gold (Au), silver (Ag), and chromium (Cr) or A metal layer such as the aforementioned alloy such as MoCr may be provided. The reflector 14 is generally thick enough to be opaque (eg, 300 nm or more). However, in other embodiments, the reflector 14 is a partial reflector for a “semi-transmissive” IMOD display. The transmittance of the reflector 14 in certain embodiments depends on the thickness of the reflector 14. In general, the metal reflector 14, which is a partial reflector, is between 20 and 300 inches, and preferably less than 225 inches. By using a thin semi-reflective layer in the reflector 14 of various embodiments of the PV-integrated display 100, the interferometric modulator can reduce the selected portion of the active array of display pixels from about 5% to about 50%. It may be configured to allow it to pass through to reach the photovoltaic material. In such a mechanism, the patterned PV black mask can be under such a transflective region and captures light passing through the transflective region.

  Although the foregoing detailed description discloses several embodiments of the present invention, it is to be understood that this disclosure is only illustrative and not limiting. It should be understood that the particular configurations and operations disclosed may be different from those described above, and that the methods described herein may be used in situations other than semiconductor device manufacturing. One skilled in the art will appreciate that certain features described with respect to one embodiment may be applicable to other embodiments. For example, various features of the interferometric stack are discussed with respect to the front surface of the photovoltaic cell, photovoltaic device or array, and such features are formed on the back surface of the photovoltaic cell, photovoltaic device or array. It can be easily applied to other interference type stacks. For example, various reflector features have been discussed with respect to various embodiments of interferometric modulators formed on the front surface of a PV device. Such reflector features are also applicable to interferometric modulators formed on the backside of a PV device, including the use of partial reflectors, or some implementations of interferometric modulators. The form is applicable to omit the reflector at the same time as using the back electrode as a reflector.

DESCRIPTION OF SYMBOLS 14 Movable reflector 16 Optical laminated body 18 Support body 19 Cavity 20 Substrate 34 Mechanical layer 65 Buffer layer 71 Column electrode 72 Row electrode 73 Rail support body 74 Gap 75 Support structure 76 Etching hole 77 Active pixel 81 PV material 82, 83 electrode 100 display device 101 active pixel 102, 103 grid line 104, 105, 105a, 105b, 105c, 105d, 106 light 107a, 107b ambient light 108 back plate 110 front PV black mask 115 back PV black mask 120 display device 130 PV integrated display device 140 PV integrated interferometric modulator array 143 Back electrode 144 Front electrode 145 Back plate 146 PV black mask island 161 Substrate 17 1 Derivative buffer layer

Claims (22)

A display device that displays an image on the front side and has a back side opposite to the front side,
An array region comprising active pixel areas and inactive areas comprising reflective microelectromechanical system (MEMS) devices;
A photovoltaic cell comprising a photovoltaic material, wherein the photovoltaic material is formed on one of the front and back surfaces of the array region, and the photovoltaic material is within the active pixel area. And a photovoltaic cell patterned to correspond to the pattern of the inactive areas including an insulated inactive area formed on the display device. The device of claim 1 , wherein the inactive area includes an area that separates adjacent active pixel areas.   The device of claim 1, wherein the photovoltaic material comprises a deposited thin film photovoltaic material.   The device of claim 1, wherein the photovoltaic material further functions as a black mask that reduces reflections of the inactive areas of the array region. The device of claim 4 , wherein the photovoltaic material is configured to reflect or transmit less than 10% of visible light incident on the photovoltaic material. The device of claim 5 , wherein the photovoltaic material is capable of receiving light from both the front surface and the back surface of the photovoltaic material. The device of claim 6 , further comprising a transparent conductive film in electrical contact with the photovoltaic material.   The device of claim 1, wherein the photovoltaic material is formed on the back surface of the array region. 9. The device of claim 8 , wherein the front electrode is separated from the back electrode by one of a dielectric buffer layer and a thinned portion of the photovoltaic material.   The device of claim 1, wherein the MEMS device comprises an interferometric modulator. The inactive area comprises a transparent inactive structure that can allow ambient light to reach the photovoltaic material, the photovoltaic material corresponding to the pattern of the inactive structure The device of claim 9 , which is patterned to do so. The device of claim 11 , wherein the transparent inactive structure comprises spaces between pixel areas.   The device of claim 1, wherein the photovoltaic material is formed on a front surface of the array region. The device of claim 13 , wherein the photovoltaic material is patterned to mask inactive areas of the array region. The device of claim 14 , wherein the MEMS device comprises an interferometric modulator. The device of claim 14 , further comprising a transparent conductive film in electrical contact with the photovoltaic material. The device of claim 16 , wherein the photovoltaic material can receive light incident on the photovoltaic material through the transparent conductive film from the front and back surfaces of the photovoltaic cell. A method of manufacturing a display device configured to display an image on a front side and having a back side opposite the front side,
Providing a display comprising an active pixel area comprising a reflective microelectromechanical system (MEMS) device and an array area comprising inactive areas;
Disposing a patterned photovoltaic material on one of the front and back surfaces of the array region, wherein the photovoltaic material is insulated formed in the active pixel area. And patterning to correspond to a pattern of said inactive areas including inactive areas. The method of claim 18 , further comprising aligning the patterned photovoltaic material with a pattern of the inactive area. The device of claim 9 , wherein the photovoltaic material forms an island of photovoltaic material. The device of claim 10 , wherein the inactive area comprises one of an etching hole or a pillar. The device of claim 10 , wherein the photovoltaic material forms an island of photovoltaic material.

Images